1. Field of the Invention
The present invention relates to a direct-fluid-supply writing implement configured so that ink is stored directly in an ink tank and that an ink occluding element is interposed between the ink tank and a pentip. Incidentally, in the present specification, the word “front” designates a side toward the pentip, while the word “rear” designates a side toward the ink tank.
2. Description of the Background Art
(1) Japanese Utility Model Examined Publication No. JP-UM-B-45-18890 discloses such a kind of a conventional direct-fluid-supply writing implement. The writing implement has an accommodating element having a communicating tube and a through hole and the accommodating element being filled with an absorbent material; an inkwell having an upper opening part in which the accommodating element inserted; a pentip inserted in the absorbent material; and a vent tube penetrating the through hole of the accommodating element; wherein an interior of the inkwell communicates with the absorbent material via the connecting tube, and an interior of inkwell communicates with ambient air via via the vent tube.
The direct-fluid-supply writing implement disclosed in the JP-UM-B-45-18890 is configured so that the vent tube always communicates with ambient air even though the communicating tube and the vent tube are provided in the upper opening part of the inkwell. Thus, in a case where a pentip downward-pointing state of this writing implement is maintained, ambient air is kept supplied into the inkwell through the vent tube. Simultaneously, ink contained in the inkwell is kept supplied to the absorbent material through the communicating tube. Consequently, there is a fear that the ink contained in the inkwell may leak out from a pentip.
(2) Further, Japanese Utility Model Examined Publication No. JP-UM-B-56-7504 discloses a felt-tip pen, which is one kind of direct-fluid-supply writing implement having a container body; an ink accommodating chamber having a ink supply port to which a sealing lid is detachably attached, the ink accommodating chamber provided a rear side of the container body; an ink absorbing member accommodating chamber having a first and second ink absorbing members provided on a front and rear side thereof, respectively; a pen tip of which base portion is held by the first absorbing member, a end surface of the base portion contacts with the second absorbing member; a partition wall separating the ink accommodating chamber from ink absorbing member accommodating chamber; and an air supply tube fixed to the partition wall, the air supply tube having a first opening abutting on the first absorbing member and a second opening provided in the ink accommodating chamber in a vicinity of the ink supply port, wherein an ink stored in the ink accommodating chamber is supplied to the absorbing member through a liquid supply hole provided on the partition wall.
The direct-fluid-supply writing implement disclosed in the JP-UM-B-56-7504 has the two absorbing members and is configured so that the first opening of the air supply tube is made to abut against the rear end surface of the first absorbing member, and that the liquid supply hole communicates with the rear end surface of the second absorbing member. That is, this direct-fluid-supply writing implement is configured so that the first opening of the air supply tube and a front end opening of the liquid supply hole are placed apart from each other in an anteroposterior direction. Thus, it is difficult to block up the opening end of the air supply tube with ink that is supplied from the liquid supply hole and is impregnated into the absorbing member (that is, to bring the opening end of the air supply tube into a liquid sealing state). The outflow of ink from the ink tank, and the inflow of air into the ink tank (that is, the exchange between the ink and the air) cannot surely be stopped. Consequently, there are fears that excessive ink may be supplied to the absorbing member, and that the ink may leak out from the pentip.
Additionally, the direct-fluid-supply writing implement disclosed in the JP-UM-B-56-7504 is configured so that the pentip penetrates through the first absorbing member and contacts the second absorbing member. Thus, it is difficult to set the longitudinal dimension of the pentip at a small value. Consequently, the cost of the pentip increases, so that this implement cannot be provided to a user at a low price. Also, the length of an ink outflow passage between the rear end and the front end of the pentip increases, so that the ability to cause outflow of ink from the pentip is degraded. Consequently, blur and discontinuity tend to occur in handwritten characters.
(3) Furthermore, Japanese Utility Model Examined Publication No. JP-UM-B-60-7191 discloses a brush-like writing implement, which is one kind of the direct-fluid-supply writing implement. The brush-like writing implement has an ink tank; a brush element; a front barrel having ink adjusting tube and an ink conduit which are coaxially disposed in the front barrel; a relay core inserted in the ink conduit, the relay core has a rear end inserted in the ink tank and a front end disposed on a rear end of the brush element with a predetermined interval; a porous ink absorbing member attached to both of the rear end of the brush element and a annular passage defined between the ink adjusting tube and the ink conduit; an air passage communicating with ambient air, formed between an inner surface of the front barrel and an outer surface of the ink adjusting tube; an ink passage formed on the rear end of the brush element and communicating with the air passage, wherein a density of the ink absorbing member at a front side is greater than that of the other part of the ink absorbing member.
The direct-fluid-supply writing implement disclosed in JP-UM-B-60-7191 is configured so that the ink tank is connected to the ink absorbing member only by the single ink conduit. Thus, at initial ink supply (that is, at the time of initially supplying ink from the ink tank to the absorbing member), air and ink cannot quickly be exchanged. It takes considerable time to bring the writing implement into a state in which the writing implement is ready for writing. Additionally, the direct-fluid-supply writing implement disclosed in the JP-UM-B-60-7191 has a large number of components and also has a complex structure. Consequently, this writing implement can be provided to a user at a low price.